BUFFALO, N.Y. (AP) -- The sounds of the last desperate minutes in the cockpit aboard Flight 3407 could be clues to the cause of a crash that came violently and suddenly, with the doomed plane dropping steeply and pitching and rolling like a rollercoaster.

Investigators in Washington and Buffalo have begun an in-depth study of the plane's voice cockpit and voice data recorders.

They also plan to scrutinize all pieces of the engines to learn whether the plane was intact when it hit the ground. Steve Chealander of the National Transportation Safety Board said the engines would be taken by crane from the debris field today.

Families of the victims visited the site today. They boarded several buses at the hotel where they are staying and drove to the crash site with police escort.

Monday: Investigators scrutinized the pilot's actions in the final moments of Flight 3407 and tried to determine whether anything on the airplane broke mid-flight, while families of the victims visited the crash site for the first time.

After a seemingly routine flight, the airplane endured a 26-second plunge before smashing into a house in icy weather about six miles from the airport Thursday night, killing 49 people on the plane and one on the ground.

Though ice has emerged as a possible factor, the cause of the crash has remained elusive in part because there was no distress call from the pilot, no mechanical failure has been identified and the plane was severely damaged by the crash.

Shortly before the crash, the crew notified air traffic controllers that there was significant ice buildup on the windshield and wings even though they had turned on the plane's deicing system shortly after leaving Newark, N.J.

National Transportation Safety Board member Steve Chealander drew attention to the crew's actions when he said Sunday that the pilot appeared to ignore recommendations by the NTSB and his employer that the autopilot be turned off in icy conditions. The autopilot remained on until an automatic system warned that a stall could occur, pushed the pilot's yoke forward and shut the autopilot off.

Chealander acknowledged that it was possible that the pilot overreacted by yanking the yoke back, further destabilizing the plane, but he said that was one of an almost unlimited number of possibilities.

Relatives of the victims made their first trip to the scene Monday. They boarded several buses at the hotel where they were staying and drove to the crash site with police escort.

Chealander said it was hoped that the last of the bodies would be removed sometime Monday.

Also Monday, more than 2,000 people, including relatives of the victims, turned out for a community prayer service.

"We feel it's a miracle that more houses weren't destroyed and more people killed," said Ora Ganschow, 79, of Clarence Center. She lives four blocks from the site; her son, John, lives two blocks away.

Wearing blue dress uniforms, members of the Clarence Center Volunteer Fire Co. carried single long-stemmed roses -- one for each victim -- to the altar, placing them into a crystal vase as a soloist sang "Amazing Grace."

Authorities said gawkers continue to seek access to the site, forcing officials to again close a road that leads to the suburban Clarence neighborhood. Three people have been arrested, including a man caught hiding behind a home and videotaping the crash site Friday.

Much of the plane has already been removed. A crane was brought in to move the engines so investigators could determine whether the engines and their blades were intact when they hit the ground.

Investigators also were looking into the flight crew's actions.

The captain, Marvin Renslow, 47, was believed to be handling the duties of the pilot during the final moments aboard the Dash 8 Q400 plane, operated by Colgan Air. He had 3,379 hours of flying experience but had only flown the Dash 8 since December.

The flight's first officer, Rebecca Lynne Shaw, 24, had 2,244 hours of experience and had flown the Dash 8 for 774 hours.

Chealander said investigators would research their histories, in part by interviewing those who had trained them.

Investigators also were preparing to analyze the plane's maintenance records and to interview mechanics, Chealander said.

The NTSB is asking pilots who were in the air around Buffalo on Thursday whether they had to deal with ice, Chealander said. He noted that the pilot of a flight that landed in Buffalo 20 minutes after the crash reported only light to moderate icing.

Even aboard Flight 3407, all seemed well until communication ended in the plane's final half minute. No distress call went out as the plane destabilized.

"At that point, from a pilot's perspective, they had their hands full. They weren't thinking about keying a microphone and saying mayday to anybody out there. They were trying to save their lives and the lives of everybody on that airplane," Chealander said.

Earlier:

On Sunday, Chealander released facts illustrating how the Continental Connection flight disappeared from radar late Thursday, plunging into a house and killing 50 people.

Chealander said information from the plane's flight data recorder indicated that the aircraft pitched up at an angle of 31 degrees in its final seconds, then pitched down at 45 degrees.

The plane rolled to the left at 46 degrees, then snapped back to the right at 105 degrees -- 15 degrees beyond vertical.

Radar data shows Flight 3407 fell from 1,800 feet above sea level to 1,000 feet in five seconds, he said. Passengers and crew would have experienced G-forces up to twice as strong as on the ground.

Authorities said today that gawkers continue to seek access to the site, forcing officials to again close a road that leads to the suburban Clarence neighborhood where the plane crashed into a house, killing all 49 people on board and one person in the home.

A road that leads to the neighborhood was reopened to traffic about 6 p.m. Sunday but closed again after residents complained that people were parking cars and then trespassing on backyards in a bid to get close, according to Capt. Steven Nigrelli of the New York State Police.

Three people have been arrested trying to get to the site, including a man caught hiding behind a home and videotaping the crash site Friday.

The plane crashed belly-first on top of a house about six miles short of Buffalo Niagara International Airport, two to three minutes from when it should have touched down on the runway.

Just before they went down in a suburban neighborhood, the pilots discussed "significant" ice buildup on their wings and windshield. Other aircraft in the area told air traffic controllers they also experienced icing around the same time.

Chealander said in an interview that the pilot may have rejected federal safety recommendations and the airline's own policy for flying in icy conditions by leaving the autopilot on even after he notified air traffic control that the flight crew had spotted ice on the leading edge of the wings and the windshield.

The Dash 8 Q400 plane, operated by Colgan Air, was equipped with a "stick shaker" and "stick pusher" mechanism that rattles the yoke to warn the pilot if the plane is about to lose aerodynamic lift, a condition called a stall. If not corrected in time, the mechanism automatically pushes the stick forward to avert a stall.

Chealander said the plane was on autopilot until the "stick shaker" and "stick pusher" kicked in, automatically putting the plane back in the pilot's hands.

At some point, the pilot switched on an anti-stall device that increases the speed of the plane by 20 knots and gives a pilot more margin to recover from a stall if it occurs.

Asked whether the pilot might have overreacted by pulling the stick back when it automatically went forward, Chealander said, "Yes, it's possible."

Still, he was careful not to be critical of the pilot.

"Everything that should have been done was done, so we keep looking," he said. "We keep looking, trying to find out why this happened."

Chealander said the plane's deicing system was turned on 11 minutes after it took off from Newark, N.J., and stayed on for the entire flight. Indicator lights showed the system appeared to be working.

He said the pilot was being "very conservative" by turning it on so soon.

Investigators who examined both engines said they appeared to be working normally at the time of the crash.

Colgan Air operates a fleet of 51 regional turboprops for Continental Connection, United Express and US Airways Express.

By Sunday, authorities had recovered the remains of 15 people from the wreckage as crews raced to finish their work before a storm expected later in the week.

Recovery crews could need as much as four days to remove the remains from the site. Chealander described the efforts as an "excavation."

"Keep in mind, there's an airplane that fell on top of a house, and they're now intermingled," he said.

DNA and dental records will be used to identify the remains, he said.

Once all the remains are recovered, the focus will turn to removing wreckage of the 74-seat aircraft from the neighborhood.